Turns out men and women with square face shapes—typified as being shorter and wider—tend to have more intense sex drives than people with circular, oval, or triangular faces, according to research from Nipissing University in Canada.

In two separate studies, published in Archives of Sexual Behavior, researchers polled college students. In the first study, 145 undergrads in sexually active relationships completed a questionnaire about how they behave with their significant others, as well as their desires, motivation, and proclivity to have sex. Participants also submitted photographs of themselves so researchers could determine their facial width-to-height ratio.

In the second study, 314 students talked about their sexual orientation and if they'd ever consider cheating on their significant other—to see how comfortable they are with the concept of casual sex.

Researchers already knew square face shapes were tied to specific psychological and behavioral traits, including aggression, dominance, and higher instances of unethical behaviors. Square-faced people also tend to be more attractive as casual sexual partners, compared to those with thinner, longer faces.

So: Why the correlation? It all comes down to testosterone. Your hormone levels at birth (and at various growth periods, like puberty) influence your sexual attitudes, just as they influence the shape of your face.